The present invention relates to a structure of a vehicle power train which comprises an engine situated lengthwise in a vehicle and a transmission disposed adjacent to the engine in parallel.
In the FF vehicle (Front engine, Front wheel drive vehicle) or FF derivative four wheel drive vehicle, a known power train has an engine situated transversely so that the axis of the output shaft of the engine extends in the widthwise direction of the vehicle body and a transmission situated to the rear of the engine in the longitudinal direction. This power train is defined as a transversaly situated power train herein below. This transversaly situated power train possesses an advantage such as a smooth transmittance of the driving power since the output shaft of the engine and input and output shafts of the transmission are parallel to an axle shaft of the front wheel. However, if the transversaly situated power train is placed on the vehicle having a normal wheel base, almost all the weight of the power train is loaded on the front wheels. Accordingly, the weight loaded on the front wheels is too large compared with the FR vehicle (Front engine, Rear drive vehicle) having an engine and a transmission situated lengthwise in a line (this power train is defined as a lengthwise situated power train herein below).
Therefore, a method that arranges the front wheel to further front than the normal vehicle so as to set the centroid to the rear of the front wheel may be taken in order to reduce the load on the front wheel. However, the wheel base between the front wheels and the rear wheels gets longer by this arrangement and the turning radius to the steering angle gets large, i.e., the steering worsens.
Also, it seems available to take another method that arranges an engine and a transmission to be disposed lengthwise in a line as the above FR vehicle so as to form a power transmission mechanism for transmitting the output of the transmission to a front wheel axle shaft. However, the transmission is situated below the passenger compartment and the tunnel part projects into the passenger compartment. This results in that the FF vehicle looses an advantage such as a wide passenger compartment.
Therefore, a power train having an engine situated lengthwise and a transmission under the engine (this power train is defined as a lengthwise situated and parallel type power train herein below) is proposed (for example, refer to the Japanese Utility Model Registration Laying Open Gazette No. 56-73940). The vehicle placed this lengthwise situated and parallel type power train passes less load on the front wheels and larger passenger compartment, as compared a vehicle having the transvarsaly situated power train.
However, since the overall height of the power train is higher and the length of a vehicle is longer in the longitudinal direction of the vehicle in this lengthwise situated and parallel type power train, there exist a problem that the power train cannot become compacted.
The object of the present invention is to provide a structure of a compact vehicle power train which lowers the load on the front wheels without causing disadvantages such as a longer wheel base and a smaller passenger compartment in a FF vehicle or a FF derivative four wheel drive vehicle.